I use one tank at a time. That way, when it runs out, I start on the other. Then I fill up the one that's empty when we return. If possible, I try to have them full during the winter. But we keep ours at the house. We have electric heat at home. If we get a bad ice storm and power goes out for a few days, we can always stay in the camper under generator power and LP heat. Its like our storm shelter.